U.S. Pat. No. 5,057,265 describes a process of the aforementioned type for the production of a car glazing equipped with a profiled frame. This known process uses a calibrated extrusion nozzle, which is positioned on the edge of the glazing and then moved all along the perimeter, where it distributes the polymer. When the nozzle has returned to its starting point after covering the entire perimeter of the glazing in order to deposit the profile there, the supply of the polymer is interrupted and the nozzle moved away from the glazing. This method makes it possible to deposit a frame on the periphery of the glazing and in particular a frame having a lip extending towards the exterior. For this purpose it is merely necessary to use a polymer, whose high viscosity enables the profile to remain in place after depositing it.
In the process described hereinbefore the finishing of the frame, i.e. the connection area between the start and finish of the extrusion is performed in a second phase after the tool has been moved away from the glass, by using an appropriate shaping device which lays on the part in question in order to give it its final shape. Numerous different polymers have proved usable for this process, but normally use is made of a one-component polyurethane, which polymerizes in atmospheric humidity. It is also possible to use two-component polyurethanes.
At the end of pressing with the special tool as described in U.S. Pat. No. 5,057,265 it is found that in the connection zone between the start and finish of the extruded joint, excess material is left behind on the joint lip, which is necessary to cut after polymerizing the joint. This is a supplementary operation, which makes it necessary to handle the glazing again at the end of polymerization. Moreover, when the polymer quantity is not in excess in the manner described above, but is instead in a slight deficit, the situation may be that a material deficiency is noted more particularly on the generally thin lip which, in the case of a car glazing, can be prejudicial to its subsequent operation when the glazing is fitted in the car.
The extrusion procedure involving the in situ extrusion of a joint on the periphery of a glazing has numerous advantages. Particularly due to its flexibility, the in situ extrusion avoids the costs of very expensive moulds as are required in the encapsulation method known as reaction injection moulding (RIM). However, although profile variations are compatible with the in situ extrusion method (cf. e.g. U.S. Pat. No. 5,108,526 or EP-A-479,677), certain complicated shapes cannot be directly produced and in particular those extending beyond the periphery of the glazing. This is particularly the case when it is wished to incorporate other functions into the joint, because they often occupy a significant amount of space.
EP-A-255,218 describes a car glazing encapsulating RIM method, in which during the injection of the joint, various devices are incorporated which are used for functions other than those conventionally exercised by car glazing joints. These are, for example, in the form of a spoiler, a driving mirror, a stop light, electrical conductors, or are intended for the distribution of water, air, etc. The RIM method used involves a single stage, the accessories being placed alongside the glazing in the mould before the start of injection and are automatically inserted in the joint of the finished glazing. The problem of inserting accessories in the vicinity of a profile extruded in the periphery of a glazing is very different and it is impossible, particularly due to the cost or nature of the polymer, to think if using the RIM encapsulation method.